TROUBLESHOOTING ELECTRICAL SYSTEMS
April 6, 2017
The last 20 years has introduced many innovations to the semi-trailer
electrical operation including the wiring harness, LED lighting, and ABS. Just
in the past several years, additional features such as tracking devices, tire
inflation, and sensing devices have been added.
These added features as an
intergraded system demand new testing tools and methods replacing the famous
switch box and the technician’s best guess. The technician needs to know his
voltage and the condition of the circuits to be displayed.
- Circuit voltage with the load which includes poor connections and corrosion
- Amperage needs to be able to read 0.01 amps
- Automatically identify good, open circuit, circuit to circuit short,
open ground, and chassis ground conditions. Note: a circuit may have more than
There are discussions about 42 volt systems and eventually the CAN ABS
requiring addition connections and added complexity that exists in the global
Electronic testing tools with dedicated software and digital readout are
absolutely required to identify circuit issues and read the ABS electronic
control unit. These tools take the guess work out of the repair with consistent
ABS will be the platform for road stability, Electronic Control Systems,
electronic braking, Auto trailer tail deployment, and who knows what else.
Since the ABS depends upon electrical power, the all-in- one testing device
will deliver the power and read the ABS as system.
The ideal diagnostic testing device must incorporate Federal standards as well
as the Technology Maintenance Council's "Recommended Practices" to fully meet
the industry’s needs. For example, power requirements for ABS operation is
clearly identified to facilitate the technicians trouble shooting efforts.
Insufficient or no power is a high percentage of inoperable trailer ABS.
A critical element of consistent trailer circuit and device testing is power
management. The ideal source voltage duplicates the tractor output at 13+
- In case of mobile operations, battery maintenance is required.
- For the shop operation, a 110 vac power supply (not converter) delivering 13.8 volts is the best solution.
Several years ago, a TMC member survey identified preferred characteristics for buying tools.
- Easy to use or "user friendly" (minimum training required or available)
- Rapid payback within a year
- Solves multiple issues such as electrical, air, and ABS troubleshooting
- Durable for shop or mobile
- Upgradable extending the life and applications.
- Vendor support and service
The future of trailer maintenance is data management. Historically, the trailer
was the forgotten sister to the tractor even though the trailer was the revenue
generator. Technology is now available to collect the trailer elements
(electrical, air, ABS, tires) automatically on a tablet in the shop. The tablet
app directs the technician thru the process to produce a DOT inspection in a
file for a printed report and data collection.
The patented VERIFIER TRAILER INSPECTION SYSTEM by LITE-CHECK is the future.
Easy to use, management has a verifiable report and data to manage the trailer
President and Founder
LITE-CHECK FLEET SOLUTIONS INC
The Technician Shortage: Reaching the Next Generation
September 16, 2016
By Sam Dascomb, LITE-CHECK | Marketing
You can feel it in every maintenance shop across the nation. Vacancies in truck and trailer maintenance shops remain open, as more and more great technicians retire. Where and how is the industry to survive without the needed youth, skilled and ready to work?
The reality is that there are over 10,000 students produced annually out of technical schools but these students aren’t turning to the traditional jobs of the trucking industry. According to Wheeltime’s George Arrants, these students are turning to “Industries like wind [power] generation”. These jobs require more technology skills than what the students would expect from truck and especially trailer maintenance.
The millennial generation has grown up with technology everywhere. It is natural that they will want to work in an environment that employs the tools that they are accustomed to. However, many maintenance shops are still using paper files and book systems for maintenance.
Incorporating and using new technologies — cloud-based data record keeping systems, tablet-based/app-based preventative maintenance inspection systems, and fully electronic testing systems — in the maintenance and repair processes of truck and trailer fleets will connect millennials with the technologies they have become so accustomed to in their daily lives. Once included, advertising the job as more technical, introducing the students to the shop through partnerships with the local technical school, and even apprenticeships become easier since the new recruits will be more adapted to the tools in the industry.
How to improve your CSA score
Has your boss tasked you with improving the vehicle maintenance portion of your company's Compliance, Safety, Accountability (CSA) score? How do you go about that? How would you change your maintenance practices to achieve the biggest impact on your CSA score? What if I told you that checking just four items on your semi-trailer during every inspection would cover 73.5 percent of the items that cause Level I inspection OOS violations? Basing your inspection and maintenance practice around these four items is a slam-dunk to lowering your road repair costs and fines, and the key to your next promotion.
We get our data from the recently released Roadcheck 2014 data, published by the Commercial Vehicle Safety Alliance (CVSA: www.cvsa.org). They tell us that in a three-day period, 49,656 Level I inspections were performed and 23 percent, or 11,421 vehicles were placed out of service. These statistics represent the state of commercial vehicles as a whole, and the OOS violations are amazingly consistent year over year. That is a good thing. It means that you can build an inspection and maintenance program that will focus on the big hitters and know that it will keep working for you into the future.
The Roadcheck 2014 OOS maintenance big-hitters are:
- Brake System 29.5 percent
- Brake Adjustment 16.7 percent
- Tires/Wheels 13.8 percent
- Lights 13.5 percent
Total 73.5 percent
The key to checking these items on a semi-trailer is to use an advanced diagnostic tester, like the LITE-CHECK 920 (www.lite-check.com/inspector-920/). What can a tester like this do for the first two items that have to do with brakes? First, this tester can perform a 60-second leak-down test on both the emergency and service lines at the same time. If you do have an air leak, it will identify which line the leak is on and whether it is an external or internal leak so you can find and fix it quickly. Using the remote control, a technician can go under the trailer and apply and release the brakes with the push of a button. This makes measuring brake stroke a simple and quick, one-man job. It also lets the technician observe the brakes during operation to check for seized or loose parts. He will be in the same position as the officer during a Level I roadside inspection, and can see and hear everything the officer will be able to. What better way to improve your odds of passing a Level I inspection than to inspect the same things the same way the officer will. We have just checked the items that cause 46.2 percent of OOS violations and it took one technician about five to 10 minutes.
The next big-hitter is tires and wheels. I suggest that you do a visual inspection of the tires and check the air pressure with a tire gauge. While the technician is under the trailer inspecting the brakes using the LITE-CHECK 920 tester, he can easily listen for air leaks from tires and inspect the inside surfaces of the tires that might be missed if an inspection is only done from the outside. Tire auto-inflation systems are nice, but they have to be checked for leaks like any other air system. This will be accomplished when the technician performs the leak-down test on both air lines previously mentioned.
Now for the simplest item that gets more commercial vehicles pulled over in the first place -- which can lead to a Level I inspection -- a light out. With the exception of the ABS light, all lights on a semi-trailer are in parallel circuits. That means you can have a light out, but the circuit continues to function and to light the other lights on the circuit. That is why a technician has to go around the trailer one time and physically check each filament in every light. This is easily done with a LITE-CHECK 920, because the remote control lets the technician activate each circuit as he passes each light to check for proper operation. Of course, a sophisticated tester does more than just light up the lights. The LITE-CHECK 920 constantly monitors each electrical circuit for opens, shorts and chassis shorts. If such a fault exists and the alarm goes off letting the technician know, the readout on the tester will identify the fault and the circuit(s) involved so the technician can begin fault isolation immediately.
And there you have it. Using an advanced diagnostic trailer tester, like the LITE-CHECK 920, a single technician can check the problem areas that account for 73.5 percent of OOS events in about 10 minutes. In addition, the tester can speak directly to any manufacturer's ABS ECU (anti-lock brake system electronic control unit) using PLC (power-line communication) technology. This lets you see vital items about the health of the ABS System so you can fix things proactively in the shop rather than reactively out on the road.
There will be over four million Level I inspections on commercial motor vehicles this year. If 23 percent of these are placed OOS, that amounts to 920,000 vehicles that are idled. When you consider that just having a CMV sitting on the roadside is costing you $500 per hour in addition to fines, customer dissatisfaction due to missed delivery times, an increase in CSA score, and an increase in insurance costs -- it makes an investment in an advanced diagnostic tester look like a good idea with a definite payback.
Dennis Zerbst, Sales
Best practices for trailer maintenance
My job takes me into trailer repair shops of every type, size and variety. Some of the maintenance programs that I have seen deserve to be buried and forgotten; but there are some worth sharing about so we can all learn and improve. After all, in the age of the FMCSA's Compliance, Safety and Accountability (CSA) program (www.csa.fmcsa.dot.gov), everyone needs all the help they can get just to maintain, let alone try to improve, their CSA score. I also informally interview CMV inspectors every chance I get so I have a pretty good idea what they see and what they are looking for during roadside inspections. Read on to find out some of the best practices to help you improve performance, save money and pass roadside inspections.
The key to fewer roadside inspections
Check your lights! The overwhelming majority of CMV inspections occur because an officer sees a light out and pulls a CMV over--such a simple thing, but one that starts a process that can lead to expensive roadside repairs and/or fines. A conservative estimate is that the time spent on the side of the road costs $500 per hour. To avoid this as much as possible, your trailer maintenance program needs an advanced diagnostic tester that lets one technician use a remote control to activate each electrical circuit as he walks around the trailer once. The best testers monitor the electrical circuits for faults and sound alarms and display the cause of the faults.
The number one reason trailers are placed OOS is due to brakes and/or brake adjustment. This is followed closely by tires being unfit for service, and next after that are air leaks. The CMV inspector is going to get under the trailer to perform a thorough visual inspection of the brake system components, and measure the brake strokes with a 90 to 100-psi brake application per TMC recommended practices. Including this test as part of your company's inspection and maintenance program on a regular basis will help you be in the best possible position to pass roadside inspections.
There is help available to make this job fast and accurate. Advanced testers let you apply and release the brakes via remote control while you are under the trailer, watching the brake components move and measuring/adjusting brake stroke length. The best testers are regulated to provide the same air pressure for a brake application as the inspector will use. Remember to do a leak-down test on both air lines at the same time. Since you are already there, conduct a quick visual inspection of the tires and listen for air leaks. With the right tester, you can check all the hot items--lights, brakes, tires and air leaks with one technician and less than 10 minutes of shop time. That is a good investment, trading 10 minutes of shop time for all of the expense and hassle of roadside inspections and/or repairs. When the wheels are turning, everybody is happy!
Another best practice is to pay for performance. Reward drivers and shop technicians for passing roadside inspections. Do this and your drivers will perform pre- and post-trip inspections without fail, and will insist the items be fixed before they head down the road. Take a chance! I am willing to bet that your reward payout will be a smaller investment than the money saved on road repairs and/or fines. Everybody wins—you are making money and as an added bonus, morale goes up too.
Want to save $$$?
The key to fast inspections and accurate fault isolation is technology. Advanced diagnostic testers help every shop tech do the job faster and help you save considerable money on parts. Consider ABS troubleshooting; many shops consider this a "black art" and so only one to two technicians or the shop supervisor take on the challenge of working on ABS faults--but with what kind of results? ABS ECU manufacturers report that 75 percent of all units returned to them under warranty are in fact good. That is a terrible percentage and makes my point that advanced diagnostic testers are needed to help analyze electrical circuits and ABS faults. The best testers use TMC Recommended Practices to make sure that the primary and secondary power to the ABS ECU are within tolerance before the ECU can be communicated with. If the ECU does not have proper power, it will only give erroneous results, so fixing the power issues is the first step.
It is my opinion that most technicians just change the ECU when presented with this scenario; when in fact, just cleaning up the corrosion and wiring issues to fix the ECU power issues would fix the problem. This is a crucial concern when you consider that the typical ECU costs between $500 and $900 and it takes on average three to four hours of shop time to change one out. Refraining from needless replacement of good ECUs could add up to some serious money-savings very quickly. Want some icing on the cake? Not spending four hours replacing a good part gives your technician the opportunity to work on other, needed jobs and the savings or increased revenue just keep adding up.
Improve performance of lower-level technicians and employee morale
Provide technicians with a rugged, all-in-one, advanced diagnostic tester, with troubleshooting diagnostic software built-in to the tester, and the performance level of your shop will go way up. The best testers are extremely intuitive and so easy-to-use that even entry-level technicians can test and diagnose air leaks, brake issues, electrical circuits and PLC ABS faults. Testers should test to TMC Recommended Practice standards to ensure that the testing is done correctly and that you are getting the expected results.
Every time I see a shop invest in an advanced diagnostic tester, it is amazing to watch how the technician morale goes way up. After a few short weeks, you will not be able to separate the technicians from their beloved tester. Testers do require an investment, but one that has a definite payback in terms of labor savings, parts savings and fewer roadside repairs. And as an added bonus, your CSA score probably improved, as well.
You have probably surmised that an advanced diagnostic tester is the key to improving your trailer maintenance performance level while saving money and passing more roadside inspections. I gave you the big hitters; if you want to do even better, just inspect those things regularly and thoroughly using advanced testers (probably not as difficult as you were thinking at the beginning of this article). Yet, some of you will say "We never needed tools like that before. We will get along just fine without them." CSA will eventually put the "nails in the coffin" of shops run with that mentality. If you travel as much as I do, you will notice that there are fewer repair shops and fewer fleets than there used to be. These were the technology laggards that failed to adapt, improve and invest in the tools required for today's trailers. I sincerely hope that you will instead embrace change and invest in your future. After all, CSA is here to stay.
Dennis Zerbst, Sales
3-Step ABS Test
January 2, 2013
Roadside Inspectors are looking more closely at the trailer ABS operation. Does the ABS warning turn on and off with the ignition. If not, a violation is possible and the problem may be very simple to repair.
The ABS malfunctions are likely power or sensor related. The majority of ECU's returned to the manufacturers are functional suggesting that the ABS repair procedures are not adequate.
A significant number of ABS malfunctions are power related. The Electronic Control Unit (ECU) requires 9.5v as specified by Technical Maintenance Council's Recommended Practices 137. This means a minimum of 10 volts is needed at the nose socket with the trailer running lights on.
There is a simple 3Step process which eliminates wasted time and part replacement. As a necessary element, confirm the battery is delivering sufficient power exceeding 11 volts without an amperage load.
The FIRST STEP is to turn on the brake circuit to verify operation. The brake circuit is the secondary power source for the ECU. With the brake circuit, does the ABS lamp turn on and off? Does the ECU module chatter signifying the brake circuit is powering up the ECU?
The SECOND STEP is to turn on the auxiliary circuit to verify operation. Again, does the ABS lamp turn on and off? Does the ECU module chatter signifying the auxiliary circuit is powering up the ECU?
In both the FIRST and SECOND STEPS, if the ECU module chatters power is sufficient for operation. If the ABS warning lamp is not functioning, check connections and the lamp.
The THIRD STEP is reading the current faults whenever the ECU is powered and the ABS lamp remains on. The most common ABS faults are sensor related such as gap spacing and connections which requires reading the ECU. After repair, the stored fault should be cleared.
LITE-CHECK has the ideal solution with the Inspector 910B light, brake, and ABS tester for trailers. The circuit operation immediately identifies circuit faults with a description on the display with a fault alarm. The operation can be performed with the full function remote control as a one person operation. Thus, the FIRST STEP and SECOND STEP operations are simple and performed within seconds.
The real secret is the Inspector 910B software containing the ABS codes for MERITOR-WABCO, HALDEX, and BENDIX systems. The ONE ABS BUTTON will automatically identify the ABS manufacturer and read the current fault. The HELP button will display the recommended practice for repair. The STORED button shows stored faults and the CLEAR screen erases the stored fault from the ECU. ECU mileage can be read with the Inspector 910B.
Click to see our ABS video
The Inspector 910B is the comprehensive tool as a "ONE PERSON, ONE TOOL, ONE PROCESS™" operation for lights, brakes, and ABS.
Bob Blair, CEO
Quality Brake Inspections
January 2, 2013
CVSA statistics reveal "60% of Out-of-Service Brake defects could have been discovered with a good pre-trip inspection". If the technician is able to apply and observe the brake operation with controlled air pressure at the axle on both the trailer and truck, these numbers will drop.
Brakes comprised the largest percentage of 52 percent, of Out-of-Service Violations (OOSV) cited in roadside inspections conducted during Road check 2011 and the percentages have not significantly changed for the past 3 years.
This suggests non-uniform or non-existent brake inspection procedures especially on the out-bound lane.
A consistent quality trailer brake inspection is possible with the right process and equipment. Too often the air pressures are not known and the inspection may require two technicians creating an unreliable process. The requirements for quality brake inspections are straight forward. Additional information is outlined in the TECHNICAL MAINTENANCE COUNCIL's (TMC) Recommended Practices.
Regulated air pressures for the trailer matching the truck operation for consistent applications.
- Excessive pressures will stress the air system creating air leaks and mechanical damage.
- Low pressures do not exercise the brake operation as in real life and may not show air loss.
Apply Emergency (supply) air before the service (control) air to prevent service brake compounding creating mechanical issues.
- Be able to perform the air test on the supply air only and then, the supply/control together.
- Identify external air loss (fittings, air line damage, hub seals, air bags, etc.)
- Identify internal air loss (valve seals, chamber leakage, etc.)
Observe the brake mechanical operation at the wheels with a remote allowing one technician to control the process with regulated air pressures.
- Slack adjustments will be correct and consistent.
- Reduce automatic slack damage by releasing pressure during adjustment.
- Verify all brake movements are in unison.
- Observe brake movement during an air leak test.
Applying these basic principles will not only reduce road issues, but also cut maintenance costs, brake wear, and tire wear.
The LITE-CHECK Inspectors vehicle tester performs the above procedures following TMC's Recommended Practices. With the full remote control operation, a complete trailer inspection should require only 5 minutes by one technician including slack adjustments. The LITE-CHECK Pedal Actuator performs the service brake operation on a truck at the axle inspection.
Bob Blair, CEO